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Combi Boiler Recommendation

Does anyone have a recommendation for a really good combi boiler? Currently, I have a Cosmogas Axia 29E (which I've had for 4 years). It's given me nothing but problems, and the company that installed it won't come out to look at it (yeah, I did a great job of picking an installer). So before it completely gives up the ghost, I'd like to replace it. Any recommendations for a really well made, reliable unit (even it costs a little more than most) would be greatly appreciated!

I am guessing that you are my customer in Santa Paula. Even if you are not... Here's an interesting product from a company that I trust. Certainly more versatile that a combi-boiler to run hot water fancoils and DHW. I personally have never installed one, but know the Prestige boilers. Anyone on the wall have experience with this product?

But watch out for your hot water useage. It is required to use low flow showers etc and mind the # of fixtures used at once. Great boiler, Prestige. Not trying to scare off but as long as your eco minded w/ water use you will be ok. Good luck.

We've had problems with this product from the get go. The first unit that was installed kept failing (no heat). This seemed to be an electrical problem that they couldn't nail down, so that one was replaced under warranty. Unfortunately (in some sense), the problems with the second unit have been more intermittent -- to be fair, there have been extended periods of time during which the unit works fine. However, there are only so many unexpected cold showers that my wife and I are willing to take before it seems that the unit just needs to be replaced. Actually, I initially wanted the thing to be overhauled. Unable to find someone local to do the job, I was willing to ship it to the U.S. distributor and have them completely refurbish the unit; but they won't do that ... sigh.

The current problem is that the low water cut-off valve gets stuck causing the unit to shut down -- at least that's what I'm inferring since a (more or less) gentle tap with a wrench results in the unit firing up again. Another recurring problem is that the safety relief valve gets stuck on open. Typically, I don't catch this right away, leading to a bit of a mess in the crawl space where the unit is installed. Also the circulator pump is seeping water at the joints. Perhaps this unit will last a long time, but we just don't trust it anymore.

Paul

Disclaimer: I know next to nothing about boilers, so take what I say with a grain of salt.

Several years ago we installed 3 combo units. It was nothing but trouble for us and our customers. You cannot get even temperature with varying flow rates. You absolutely need low flow faucets and shower heads. Combos might work in California, FLorida and parts of Europe where incomming water comes in at 60F, but it does not work at all in colder climates.

The NTI is a fine product. We have installed probably 150 or so in the last few years before the Lochinvar Knight came along. The Knight is a much more sophisticated and reliable product for the same price. The NTI has a recall on the pvc condensate drain fitting. It will crack and spill CO into the dwelling.

I've had the axia 29e now for two years - worst mistake I've ever made. Propane bills are HUGE-out of sight!!! 500+ gallons/month and it won't raise temp over 62 degrees when outdoor temp goes below 20. Cuts off constantly for no reason - have to have one person man the unit to reset the boiler when it goes off while someone is showering. Often wake up to cold house with boiler cycling endlessly as it tries to reignite. Terrible customer service from Mestek. My contractor has tried to get help after his mechanical sub simply refused to deal with the problems and Mestek won't respond. And I'm not one of the people on the blog you will find elsewhere online about similar problems and reaction from the company. Lawsuits have been filed by others here in NM. I WOULD NEVER BUY THIS UNIT AGAIN! For the same money you can get a much better mod/con boiler.

The Prestige Excellence is a great boiler and it delivers 180 GPH of domestic hot water. If you need more hot water use their Prestige Solo with Smart 30 Gallon to 120 Gallon indirect water heater. If you have a Prestige Excellence installed and find out you need more hot water go from the indirect in the boiler to a 30, 40 or 50 gallon electric water heater.

We bought a house (nearly $1million) in Santa Fe and it has a Cosmogas Axia unit that heats the floor (radiated floor heating) and supplies hot water for the kitchen/baths. This thing is literally a piece of crap. The manual sucks (and I am an engineer saying that!) and you are left hanging with vague "troubleshooting"

instructions. Plumbers tell you flat out to get rid of it, that it is totally inefficient and problematic. Our propane bills were outrageous ($700 per mo) in the winter (and it was a "warm" winter). The thing just quit with a red "low pressure" light and the manual is completely vague about what to do. The unit cycles on and off (when set to 140 degrees) every few minutes, working itself to death. I would strongly recommend that you avoid any home with this system in it. Does anyone know of the lawsuits I have heard about against them?

I did a couple of Viessman Vito-100 with the combi-pac earlier this year, very nice and affordable set up.

The combi-pac "or what ever they call it" is an add-on to a Viessman vito 100, It uses the very cool Grundfoss vortex flow meter, sensors on the domestic supply and return, a flat plate HX, variable speed pump and a very compact engineered plastic pipe and impeller housing that ties all the components together in an easily serviceable package.

I'v been doing Viessman since they were "expensive and exotic", the new line is very competitive on price. Before you buy a TT, have a look at what's involved in opening the combustion chamber. Viessmann is a breeze to open it uses a honywell gas valve and the same ebm papst blower as just about everyone else, It's not exotic and it has a established reputation for quality and reliability.

I don't quite understand why Viessmann does not have a larger share of the NA condensing boiler market. I think it may be related to the fact that their original offerings were quite expensive and a bit difficult for a lot of americanized installers to understand. This is no longer the case and you guys who are wedded to triangle tube etc., should have a look at a company that actually has the metallurgical capability to build their own stainless heat exchanger.

I'm installing my first viessmann combi-kit in the next couple of days, looking forward to it!

Around here the viessmann vitodens 100 is king, all of our competition (5 or6 companies) install nothing but. We were the first in the area to use viessmann too, since 94 or so, tried something different once in a while (triangle, nti, baxi) but none compare to viessmann for ease of installation, start-up, reliability & service.

I'm installing my first viessmann combi-kit in the next couple of days, looking forward to it!

Around here the viessmann vitodens 100 is king, all of our competition (5 or6 companies) install nothing but. We were the first in the area to use viessmann too, since 94 or so, tried something different once in a while (triangle, nti, baxi) but none compare to viessmann for ease of installation, start-up, reliability & service.

Glad to here that the V is doing well I your area, I'm proud to be a bit different from the rest of the pack, but I don't understand why the brand is a but underrepresented in my area. When it's so clear to me that it's the front runner. When I have used other brands it often had something to do with a home owner preference, some think Viessmann is going to be like maintaining a troublesome VW. , that it exotic and not widely understood, sometimes it's best not to argue with these people, although I've become more ardent in insisting that Viessmann is the one. I think you will like the vito combi, I had bad luck with some thread fittings (not Viessmann supplied) and I found the O-ring conections w/ stainless locking clips on the "pac"to be very helpfull, (eliminated destructive disassembly).

If orings and plastic fittings scare you be warned, I found the construction innovative,the plastic intake manifold on my 11 year old Toyota is doling fine, there are shapes that can be made in plastic that would be very expensive to cast or machine from metal, plastic is our friend:)

Been selling it since around 1993 with the Vitola being the workhorse and in the past few years with hundreds of the new generation of Vitodens. Cast iron failures zero, Vitodens issues zero. While no product is failure proof I can honestly say I've seen less Viessmann issues in more then 20 years then I've seen in the last year of competitor models.

I agree and feel the same way, The Viessmann stigma is high price which scares contractors away but over the last 5 years it is no longer a true statement. Vitodens 100 and Vitorond 100 are competativley priced, superbly constructed and Viessmann as a company is more then must a boiler company. They have been and always will be a step ahead of all competitors. The next generation of Vitodens is going to blow everyones minds and I don't mean the WIFI ready that has been in service for the last year across the pond that will be here next year. What would you think if I had a condensing boiler that could provide 40-50% more efficiency then todays condesing boilers?

"The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."

The one thing I like about it is the built in diverting valve which allows you to essentially use the pump in the combi plus unit as either the primary pump in a primary/secondary system when it is not being used to pump through the plate exchanger, or to serve a basic load if the pump has enough flow/head to pump through the boilers heat exchanger and whatever other load you have (which I believe is sort of similar to the old Vitodens 200 6-24C combi but theres was built into the cabient). In a sense you had a smaller heating load, the Combi-Plus system COULD allow you to get away with just one pump for your entire system, AND it'd have a nice, simple, clean aesthetically pleasing appearance in that regard.

I find Rinnai the best mod/con, to meet, almost all applications out here...Great support, if needed, comes with low loss heater..Local training available to installers...clean, simple neat and works fine, lasts a long time....I did my homework before installing one..30 year installer ja

these to be pretty reliable. I have serviced a few of these and the fixes were pretty straight forward. Was it piped properly? Has anyone got training on the unit? A $700 / mo gas bill suggests that either no insulation in the walls or or poor design... got any pictures?

we have this unit and what a piece of crap- almost everything imaginable has been replaced, no one in our area can work on it and when they call support they never receive a call back. I would like to stick this up someones %##!!. We live in the upper peninsula of michigan and efficient it is not. My 4800 sq.ft home costs $800.00 a month to heat when it is running! I would like to sue the heck out of these people!

we have this unit and what a piece of crap- almost everything imaginable has been replaced, no one in our area can work on it and when they call support they never receive a call back. I would like to stick this up someones %##!!. We live in the upper peninsula of michigan and efficient it is not. My 4800 sq.ft home costs $800.00 a month to heat when it is running! I would like to sue the heck out of these people!

more about what you are having for issues? Give more info about you home. Gas type? Heater (baseboard, cast iron, radiant) Age of you place? etc.... I have a number of these out there.... i also have worked on a bunch of these and have some factory training....

I stumbled across this website BLOG looking for some Axia 29E parts, or knowledgeable techs.

I will attempt to provide sufficient answers and relevant resources to address all of the issues that I am reading about the Axia 29E.

I live near Saranac Lake, NY where it gets -40 degrees to -60 degrees many winters, even if only for a few days each year.

My nephew is a licensed HVAC tech, commercial and residential. The old part of my business has baseboard heat, and the 2000 year

addition has in-floor PEX in the cement with 8 zones. Three propane boilers, and a digital controller. My nephew and I put an Axia 29E

in my home in 2007, and now I need some igniter parts, and will be good to go again.

~ ~

My answers for many of the issues on this web page.

The current problem is that the low water cut-off valve gets stuck causing the unit to shut down -- at least that's what I'm inferring since a (more or less) gentle tap with a wrench results in the unit firing up again. Another recurring problem is that the safety relief valve gets stuck on open. Typically, I don't catch this right away, leading to a bit of a mess in the crawl space where the unit is installed. Also the circulator pump is seeping water at the joints. Perhaps this unit will last a long time, but we just don't trust it anymore. Paul Disclaimer: I know next to nothing about boilers, so take what I say with a grain of salt.

have to have one person man the unit to reset the boiler when it goes off while someone is showering.

Often wake up to cold house with boiler cycling endlessly as it tries to reignite.

Too cold at the tank = Low volume flow, or no flow = out of gas.

~ ~

Problems -02)

(COLD Outside where the Propane tank is.)

It won't raise temp over 62 degrees when outdoor temp goes below 20.

Boiler cycling endlessly as it tries to reignite.

~ ~

we bought a house in Santa Fe and it has a Cosmogas Axia unit that heats the floor (radiated floor heating) and supplies hot water for the kitchen/baths.

Our propane bills were outrageous ($700 per mo) in the winter (and it was a "warm" winter). The thing just quit with a red "low pressure" light and the manual is completely vague about what to do. The unit cycles on and off (when set to 140 degrees) every few minutes, working itself to death.

~ ~

Problems -03)

Axia unit that heats the floor (radiated floor heating).

The unit cycles on and off (when set to 140 degrees) every few minutes, working itself to death.

Our propane bills were outrageous ($700 per mo) in the winter (and it was a "warm" winter).

The Axia 29E recovers very quickly, and 140 degrees may be too much heat for the {PEX, I am presuming} to last very many years.

An HVAC engineer could design a crossover radiator and storage tank with its own circulator to keep the floor heat even.

The unit cycles on and off is called "Short cycling" caused by the furnace catching up to the "Load" very quickly and turning itself off.

This is a POOR Installation design; nothing to do with the Axia. You will have the same problem with every furnace, until the issue is fixed.

~ ~

Problems -04)

We live in the upper peninsula of michigan (COLD) and efficient it is not. (COLD Outside where the Propane tank is.)

My 4800 sq.ft home costs $800.00 a month to heat when it is running!

~ ~

ANY AREA OF THE U.S. that gets colder than Freezing more than a day or so; needs an underground Propane Tank Install.

dose anyone have suggestion for cosmogas combo, domestic hot water ok , thermostat calls for heat raditors get hot but pressure guage rises and and cuts out boiler , no lights on indicator panel, boiler is about years old thanks

I have a Cosmogas Axia 29E. As the winter was beginning, it started having issues. As someone was showering, the heat would just cut off. The thermostat would immediately start dropping. The only way to get it back on would be to turn the unit off and then back on. Whenever the weather warmed up a bit, the problem would reoccur. Of course it never happened when the repairman came out to look at it. And then the unit stayed on for the whole winter. No problems. Now that it has warmed up, it cut off again. Now, even turning the unit off and back on won't get it started. It makes a sound like it is trying to ignite the heat source for about three seconds but no dice. The temperature just stays low. The water pressure seems to be fine and no red light on. Gas supply to house seems to be fine. Any idea as to what part might need replacing?